From a technical
bulletin on the PDP-1 (Programmed Data
Processor), dated March 1960: "...a compact,
solid state general purpose computer with an
internal instruction execution rate of 100,000 to
200,000 operations per second. PDP-1 is a single
address, single construction, stored program
machine with a word length of 18-bits operating
in parallel on 1's complement binary
numbers."